Generally, a motor has a stator and a rotor rotatably disposed inside or outside the stator. The stator includes a stator core having a circular base and a plurality of teeth formed radially around the outer or inner peripheral surface of the base.
So as to wind coils on the teeth, insulation treatment should be conducted on the surface of the stator core having the teeth, and accordingly, an insulator, which is made of an insulating plastic material, is coupled to the stator core so as to insulate the surface of the stator core from the coils. Alternatively, insulating powder is coated on the surface of the stator core, or an insulating film made of insulating resin is inserted into a slot between the neighboring teeth.
In case of a motor for rotating a washing tub of a washing machine, on the other hand, the motor having a stator is coupled to a body of the washing machine by means of coupling parts protrudedly formed from the inner peripheral surface of the stator. Conventional stators having such coupling parts have been disclosed in Korea Patent Nos. 10-301492 (Prior art 1), 10-0808194 (Prior art 2), and 10-1135333 (Prior art 3).
Referring to Prior art 1, coupling parts are formed every steel plate, and next, the plurality of steel plates are punched and laminated to top of each other, thus completing the formation of the stator core and the coupling parts.
Referring to Prior art 2, upper and lower insulators are coupled to the upper and lower portions of the stator core, and the coupling parts are formed on each insulator, so that when the upper and lower insulators are coupled to the stator core, the formation of the coupling parts is finished.
Referring to Prior art 3, L-shaped coupling parts are attached to the inner peripheral surface of the stator core, and next, insulating powder is coated on the entire surface of the stator core.
In case of Prior art 1, however, the coupling parts are formed every steel plate, thus undesirably increasing the quantity of steel plate consumed and the quantity of scrap generated therefrom. Further, the formation of the coupling parts is applicable in case where the steel plates are laminated to constitute the stator core, but it is not applicable in case of a spiral stator core in which the stator core is laminated in a spiral shape.
In case of Prior art 2, separate molds are needed for manufacturing the upper and lower insulators, and further, when the upper and lower insulators are coupled to the stator core, the slots between the teeth are reduced in size due to the thicknesses of the upper and lower insulators to cause the limitations in the number of turns of coils, so that electromagnetic characteristics required for the stator do not satisfy a user's needs. Furthermore, the quantity of plastic resin used for forming the coupling parts is increased to cause high manufacturing cost.
In case of Prior art 3, the insulating powder is coated after the L-shaped coupling parts have been coupled to the stator core, and accordingly, the insulating powder should be coated on the entire surface of the stator core, thus increasing the quantity of insulating powder consumed. Further, the L-shaped coupling parts are attached by means of typical welding, which does not ensure their rigid coupled result.
Therefore, there is a definite need for the development of a new stator for a motor capable of solving the above-mentioned problems.